Trouble propagating logging configuration

[Loris Bennett]

"Dieter Maurer" <dieter at handshake.de> writes:

> Loris Bennett wrote at 2021-8-31 15:25 +0200:
>>I am having difficulty getting the my logging configuration passed on
>>to imported modules.
>>
>>My initial structure was as follows:
>>
>>  $ tree blorp/
>>  blorp/
>>  |-- blorp
>>  |   |-- __init__.py
>>  |   |-- bar.py
>>  |   |-- foo.py
>>  |   `-- main.py
>>  `-- pyproject.toml
>>
>>whereby the logging configuration is done in main.py.
>>
>>After thinking about it, I decided maybe the inheritance wasn't working
>>because main.py is in the same directory as the other files.
>
> Should you speak about Python's `logging` module, then
> the "inheritance" does not depend on the source layout.
> Instead, it is based on the hierarchy of dotted names.
> It is completely up to you which dotted names you are using
> in your `getLogger` calls.

Yes, but to quote from https://docs.python.org/3.6/howto/logging.html#logging-basic-tutorial:

  A good convention to use when naming loggers is to use a module-level
  logger, in each module which uses logging, named as follows:

    logger = logging.getLogger(__name__)

  This means that logger names track the package/module hierarchy, and
  it’s intuitively obvious where events are logged just from the logger
  name.

so in this case the source layout is relevant, isn't it?

> Furthermore, the place of the configuration (and where in the
> code it is activated) is completely irrelevant for the "inheritance".

OK, so one issue is that I was getting confused by the *order* in which
modules are being called.  If I have two modules, 'foo' and 'bar', in
the same directory, configure the logging just in 'foo' and then call


  foo.some_method()  
  bar.some_method()  

then both methods will be logged.   If I do

  bar.some_method()  
  foo.some_method()  

then only the method in 'foo' will be logged.

However, I still have the following problem.  With the structure

  $ tree .
  .
  |-- log_test
  |   |-- __init__.py
  |   |-- first.py
  |   `-- second.py
  |-- pyproject.toml
  |-- README.rst
  |-- run.py
  `-- tests
      |-- __init__.py
      |-- config
      `-- test_log_test.py

I have __name__ variables as follows:

  __file__: /home/loris/log_test/log_test/first.py, __name__: log_test.first
  __file__: /home/loris/log_test/log_test/second.py, __name__: log_test.second
  __file__: ./run.py, __name__: __main__

If I have

  [loggers]
  keys=root,main,log_test           

in my logging configuration and initialise  the logging in run.py with

  logging.config.fileConfig("/home/loris/log_test/tests/config")
  logger = logging.getLogger()

or

  logging.config.fileConfig("/home/loris/log_test/tests/config")
  logger = logging.getLogger("log_test")

then only calls in 'run.py' are logged.

I can obviously initialise the logging within the subordinate package,
i.e. in 'log_test/__init__.py', but that seems wrong to me.

So what is the correct way to initialise logging from a top-level script
such that logging is activated in all modules requested in the logging
configuration?

> For details, read the Python documentation for the `logging` module.

If they were sufficient, I wouldn't need the newsgroup :-)

Thanks for the help,

Loris
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